This invention relates generally to digital thermometers of the thermocouple type and more particularly to an error compensating network for such digital thermometers.
Thermocouple sensing thermometers are generally well known. In such thermometers, the dissimilar metals forming the thermocouple junction are located within a temperature region to be monitored and generate an electrical potential that is compared with a D.C. reference voltage to measure the temperature being sensed. A temperature measuring error is introduced in such thermometers because of ambient temperature variations to which the thermocouple terminals are exposed outside the monitored region. The use of a separate external cold junction or a reference junction connected to the thermocouple have been proposed for error compensating purposes. Such error compensating means are necessarily accompanied by an additional reference voltage source and other circuit complicating components that increase the cost and calibrating difficulties associated with such thermometers.
It is therefore an important object of the present invention to provide a digital thermometer having a thermocouple sensor with an error compensating network incorporated therein to nullify the effect of ambient temperature variation in an effective and economical manner and avoiding the complexities and problems associated with prior art error compensating arrangements.